1/*
2 * The Industrial I/O core, software IIO devices functions
3 *
4 * Copyright (c) 2016 Intel Corporation
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
9 */
10
11#include <linux/module.h>
12#include <linux/init.h>
13#include <linux/kmod.h>
14#include <linux/list.h>
15#include <linux/slab.h>
16
17#include <linux/iio/sw_device.h>
18#include <linux/iio/configfs.h>
19#include <linux/configfs.h>
20
21static struct config_group *iio_devices_group;
22static const struct config_item_type iio_device_type_group_type;
23
24static const struct config_item_type iio_devices_group_type = {
25 .ct_owner = THIS_MODULE,
26};
27
28static LIST_HEAD(iio_device_types_list);
29static DEFINE_MUTEX(iio_device_types_lock);
30
31static
32struct iio_sw_device_type *__iio_find_sw_device_type(const char *name,
33 unsigned len)
34{
35 struct iio_sw_device_type *d = NULL, *iter;
36
37 list_for_each_entry(iter, &iio_device_types_list, list)
38 if (!strcmp(iter->name, name)) {
39 d = iter;
40 break;
41 }
42
43 return d;
44}
45
46int iio_register_sw_device_type(struct iio_sw_device_type *d)
47{
48 struct iio_sw_device_type *iter;
49 int ret = 0;
50
51 mutex_lock(&iio_device_types_lock);
52 iter = __iio_find_sw_device_type(d->name, strlen(d->name));
53 if (iter)
54 ret = -EBUSY;
55 else
56 list_add_tail(&d->list, &iio_device_types_list);
57 mutex_unlock(&iio_device_types_lock);
58
59 if (ret)
60 return ret;
61
62 d->group = configfs_register_default_group(iio_devices_group, d->name,
63 &iio_device_type_group_type);
64 if (IS_ERR(d->group))
65 ret = PTR_ERR(d->group);
66
67 return ret;
68}
69EXPORT_SYMBOL(iio_register_sw_device_type);
70
71void iio_unregister_sw_device_type(struct iio_sw_device_type *dt)
72{
73 struct iio_sw_device_type *iter;
74
75 mutex_lock(&iio_device_types_lock);
76 iter = __iio_find_sw_device_type(dt->name, strlen(dt->name));
77 if (iter)
78 list_del(&dt->list);
79 mutex_unlock(&iio_device_types_lock);
80
81 configfs_unregister_default_group(dt->group);
82}
83EXPORT_SYMBOL(iio_unregister_sw_device_type);
84
85static
86struct iio_sw_device_type *iio_get_sw_device_type(const char *name)
87{
88 struct iio_sw_device_type *dt;
89
90 mutex_lock(&iio_device_types_lock);
91 dt = __iio_find_sw_device_type(name, strlen(name));
92 if (dt && !try_module_get(dt->owner))
93 dt = NULL;
94 mutex_unlock(&iio_device_types_lock);
95
96 return dt;
97}
98
99struct iio_sw_device *iio_sw_device_create(const char *type, const char *name)
100{
101 struct iio_sw_device *d;
102 struct iio_sw_device_type *dt;
103
104 dt = iio_get_sw_device_type(type);
105 if (!dt) {
106 pr_err("Invalid device type: %s\n", type);
107 return ERR_PTR(-EINVAL);
108 }
109 d = dt->ops->probe(name);
110 if (IS_ERR(d))
111 goto out_module_put;
112
113 d->device_type = dt;
114
115 return d;
116out_module_put:
117 module_put(dt->owner);
118 return d;
119}
120EXPORT_SYMBOL(iio_sw_device_create);
121
122void iio_sw_device_destroy(struct iio_sw_device *d)
123{
124 struct iio_sw_device_type *dt = d->device_type;
125
126 dt->ops->remove(d);
127 module_put(dt->owner);
128}
129EXPORT_SYMBOL(iio_sw_device_destroy);
130
131static struct config_group *device_make_group(struct config_group *group,
132 const char *name)
133{
134 struct iio_sw_device *d;
135
136 d = iio_sw_device_create(group->cg_item.ci_name, name);
137 if (IS_ERR(d))
138 return ERR_CAST(d);
139
140 config_item_set_name(&d->group.cg_item, "%s", name);
141
142 return &d->group;
143}
144
145static void device_drop_group(struct config_group *group,
146 struct config_item *item)
147{
148 struct iio_sw_device *d = to_iio_sw_device(item);
149
150 iio_sw_device_destroy(d);
151 config_item_put(item);
152}
153
154static struct configfs_group_operations device_ops = {
155 .make_group = &device_make_group,
156 .drop_item = &device_drop_group,
157};
158
159static const struct config_item_type iio_device_type_group_type = {
160 .ct_group_ops = &device_ops,
161 .ct_owner = THIS_MODULE,
162};
163
164static int __init iio_sw_device_init(void)
165{
166 iio_devices_group =
167 configfs_register_default_group(&iio_configfs_subsys.su_group,
168 "devices",
169 &iio_devices_group_type);
170 return PTR_ERR_OR_ZERO(iio_devices_group);
171}
172module_init(iio_sw_device_init);
173
174static void __exit iio_sw_device_exit(void)
175{
176 configfs_unregister_default_group(iio_devices_group);
177}
178module_exit(iio_sw_device_exit);
179
180MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
181MODULE_DESCRIPTION("Industrial I/O software devices support");
182MODULE_LICENSE("GPL v2");
183